#include<stdio.h>
#include<assert.h>
int main()
{
	int my_strlen(const char*);
	char arr[] = "i want to eat an apple!";
	printf("%d\n", my_strlen(arr));

	return 0;
}
int my_strlen(const char* arr)
{
	assert(arr != NULL);
	int ret = 0;
	while (*arr)
	{
		ret++;
		arr++;
	}
	return ret;
}